The DHW formalism is one of the quantum kinetic approaches that is widely adopted to study vacuum pair production in multidimensional electromagnetic fields Ref. [1]}, [2]}. It enables one to obtain phase space information about the particles created in vacuum, so that much can be learned about Schwinger pair production process. However, the deficiency of this method is the complicated computational process because one has to solve a set of multidimensional partial differential equations. Therefore, we choose to rely on numerical simulation method used in the previous work [1]}.
